沙坡头植被固沙区生物结皮的发育特征

Development characteristics of biotic crusts on Shapotou vegetated sand dunes

对沙坡头人工植被区内生物结皮的生物特征和非生物特征进行了调查,利用时空代换法研究了该地区生物结皮的发育和演替特征。结果表明:生物结皮层有着较快的成土过程,随固沙年限的增加,生物结皮的厚度以及结皮中粘土所占的比例增加,容重呈下降趋势;在各固沙年限的生物结皮覆盖区,构成生物结皮的主要优势生物成分为地衣、藻类和苔藓。不同发育年限和不同沙丘部位各类生物结皮的盖度的调查揭示,生物结皮的形成和发育有着重要的生物过程。对沙坡头植被固沙区生物结皮的演化过程进行了系统分析,发现生物结皮是在流沙固定过程中生物成分和非生物成分相互作用的产物,是降尘累积过程、生物过程和成土过程3个阶段的统一,并依据其发生学特点给出了3个发育阶段的定性划分。

In this paper, the biological and non-biological characteristics of biotic crusts on Shapotou sand dunes fixed with artificial vegetations were investigated, and the method of using time as the substitute of space was applied to study the development and succession patterns of the crusts. The results showed that the biotic crusts had a rapid soil formation process. Along with the duration of dune fixation, the thickness of the crusts and the clay content in them increased, while the bulk density showed a declining tendency. Lichen, algae, and moss were the dominant biotic species, and the formation and development of the crusts was also an important biological process. The development of the crusts involved the interactions between biotic and abiotic components during sand fixation, and was also a process of clay accumulation, biotic species development, and soil formation. A qualitative classification of three development stages of the crusts was summarized, based on the characteristics of their genesis.